Refrigerating apparatus



March 12, 1940. w. H. TEETER REFRIGERATING APPARATUS Filed Oct. 29, 1937 3 Sheets-Sheet 2 I N VENT OR. w BY m u n n 1 I V I I ATTORNEYS.

March 12, 1940. w. TEE-[ER 2,193,243

REFRIGERATING APPARATUS Filed oct. 29, 1957 s Sheets-Sheet s INVENTOR.

BY W MW? 324/ ATTORNEYS.

Patented Mar. 12, 1940 UNITED STATES REFRIGERATING APPARATUS Wilford H. Teeter, Dayton, Ohio, assignor to General Motors Corporation, Dayton, Ohio, a corporation of Delaware Application October 29, 1937, Serial No. 171,747

10 Claims. (Cl. 230-228) This invention relates to refrigeration and more particularly to compressor mechanism for use in a refrigerating system.

In modern installations it is necessary to provide small, efficient and silent compressors. In order to provide a silent and, at the same time, eflicient compressor, it becomes-necessary to pay particular attention to the valve structure used. It is essential to design the valve so as to provide a minimum clearance at the end of the piston stroke; andit is also desirable to provide a quickacting valve which is silent in operation. One big difliculty in designing a valve is that a valve which is quick acting is usually noisy. l5 Applicant's invention is, therefore, directed to the provision of a quick acting valve which permits a maximum amount of vapor to pass through in a given time with a minimum amount of noise.

An object of the present invention is to provide an improved compressor having streamlined valve ports.

Another object of the present invention is to provide a valve structure in which the velocity of the gas flowing through the valve port is increased and the velocity of the valve disc is decreased.

Still another object of this invention is to provide a compressor through which the gas may pass with a minimum amount of change in the direction of flow of gas through the compressor.

Still another object of this invention is to provide a valve structure which is simple to manufacture'.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings:

Fig. 1 is a view partly diagrammatic showing a portion of the compressor in section;

Fig. 2 is a fragmentary sectional view corresponding to the view in Fig. 1 but with the piston moved away from the head end of the cylinder;

Fig. 3 is a sectional view taken on line 3-3 of 1;

Fig. 4 is a sectional view taken on line 4-4 of Fig. 1;

Fig. 5 is a sectional view taken on line H of Fig. 1;

Fig. 6 is a fragmentary sectional view on an enlarged scale illustrating the flow of gas through the valve port in the end wall of the piston; and

Fig. 7 is a fragmentary sectional View showing a modified valve structure for use in the second stage piston. Referring to the drawings which illustrate the present invention, I have shown a refrigerating system comprising a two-stage compressor generally designated by the reference numeral III which discharges refrigerant under pressure through a conduit l2 to the condenser 14. The condensed refrigerant flows into the receiver l6 which supplies liquid refrigerant to the evap- 10 orator la in the usual manner. Expansion valve 20 is provided in the line from the receiver to the evaporator and functions so as to control the flow of refrigerant from the receiver to the evaporator. A motor 22 is provided which drives 15 the crank shaft '24 of the compressor through the belt 26. A switchv28 controls the operation of the motor 22. An expansible bellows 30 connected by a pipe 32 to a bulb 34 mounted in thermal exchange relationship with the evaporator l8 and having a volatile fluid sealed therein actuates the switch 28.

The compressor comprises a main casing 36 having two cylinders 38 and 40. Rotation of the shaft 24 which is provided with the usual crank 25 arms 42 causes simultaneous reciprocation of the pistons 44 and 46. Valve plates 48 and 50 are provided at the head end of each cylinder. Refrigerant vapor leaving the evaporator l8 enters the compressor through the cylinder head 52 30 and upon downward movement of the piston 44 is withdrawn from the head 52 through a series of openings 53 communicating with the main port 54 provided in the valve plate 48. A valve disc 56 is provided on the discharge side of the port. 35 On upward movement of the piston 44, the valve disc 56 closes the port 54 and the gas escapes from the upper end of the cylinder 38 through the valve port 58 in the upper end of the piston 44. 'A valve disc 60 is provided for the port 5! 40 that prevents the return of the gas when the piston begins its downward movement.- The ports 54 and 5.8, it will be noted, have been streamlined, that is, the ports have been designed so as to furnish a minimum amount of resistto ance to the flow of fluid through the port.

In the second stage of compression, the downward movement of piston 46 causes the partially compressed gas in the crank case to flow upwardly through the port 62 which is provided with 50. a valve disc 64. As the piston 46 begins its upward movement, the valve disc 64 closes the port 62 and the gas compressed by the piston 46 discharges through the valve port 66 into the cylinder head 81. The port 6 is provided with a valve disc 69. Upon change in direction of movement of the piston 46, the valve disc 68 closes the port 66. As shown in the drawings. the ports l4, I8, 62 and 86 have all been streamlined so as to permit the maximum flow of gas through the port with the minimum amount of resistance to the flow of gas therethrough.

Furthermore, the ports have been arranged so as to discharge the refrigerant against the respective valve discs at an angle. The shape of each port-together with the angular relationship between the port and the valve disc makes it possible to substantially double thevelocity of the gas flowing through the port without increasing the valve disc velocity. The construction is such that a lower valve lift is possible and this results in a decrease in the velocity of the valve disc during opening and closing movement.

Referring to Fig. 6, it will be noted that, with my construction, the angle of change in the direction of flow of the gas is not very great, with the result that the gas flowing through the compressor makes very little noise. With my arrangement, eddy currents set up behind the valve disc tend to limit the movement of the disc so as to materially improve upon the operation of the valve. Inasmuch as the valve lift is less with my construction than with previous constructions, the valve operates very quickly with a minimum amount of noise.

Referring to Figs. 2 and 3, it will be noted that the valve plate 48 is provided with a plurality of apertures 63 which communicate with the main valve port 64. In constructing the port 64 the plate 48 is recessed on its under side adjacent the apertures 53, and a discor washer member 12 is fastened into the recess by means of abolt 14, the head 15 of which serves to hold the valve disc 66 in place and also serves as astop for the valve disc 56. The shape of the disc or washer I2 and the shape of the recess in the valve plate 48 is such as to provide a streamlined passage for the flow of gas. By virtue of this construction the velocity of the gas flowing through the port 53 increases as the gas approaches the outlet side of the port. Heretofore, it has been necessary to limit the velocity of the .gas flowing through the ports so as to prevent too rapid movement of the valve disc and also to prevent excessive noise produced by the hi h velocity of the fluid. I have found that with my arrangement I can substantially double the velocity of the fluid without any increase in noise and without any decrease in valve operating ciliciency.

As best shown in Figs. 1, 2 and 5, the piston 44 is constructed with on opening in the valve end .-of the piston; and a valve supporting. member 16 spring-pressed against the inner end wall of the piston and carries on its outer face the valve disc 68 and the valve supporting plate 18 which, as shown, is in the form of a bolt head. The bolt head 18 is provided with an annular groove 80 on its under side which has one or more gas passages 82 which permits gas to enter the chanhe] 80, thereby relieving the suction which might ber 16 and the wrist pin holder 86 secured to the piston by means of a pair of bolts 88.. The valve supporting member l6 is provided with a spacing flange 98 whichserves to position the amazes valve plate 60 and also serves to' position the valve plate 18. While I have shown a channel member 88 only in the valve plate 18 it is understood that similar channels may be provided in the other valve plates for the same purpose. The valve disc 68 is similarly held in place by the spring 9| which has one end pressing against theretainer 92.

Fig. 7 shows the piston 46 provided with a modifled form of valve supporting structure. It will be noted that the piston is provided with a spider member 94 which serves to support the centrally disposed valve plate or washer 96. The

' valve plate 96 is provided with a sleeve 98 which frictionally engages the bore of the spider member 94. In manufacturing. the piston and valve assembly, it is important that the upper surface of the piston 46 and the upper surface of member 98 be even so as to provide a proper seat for the valve disc 84. It is desirable, therefore, that the valve surfaces be machined while parts 46 and 96 are in assembled relationship. Inasmuch as there is no chance to machine the valve surfaces after the valve disc is in place, the member 96 is held in place during the machining operation by means of the close flt between the sleeve 98 and the bore of the spider 94. After the surfaces have been machined, the retaining bolt Illlland the valve disc 64 are assembled. It will be noted that the head of the bolt I98 serves as a stop for the valve disc 64. Under normal operation, however, the eddy currents set up by the flow of gas through the valve port limit the movement of the valve disc so as to prevent it from striking against the stop member. It is to be understood that the washer member 12, for example, may likewise be provided with a flange corresponding to the flange 98 in order to facilitate accurate machining of the valve seat.

It is apparent, therefore, that I have provided a simplified compressor which is very silent and eflicient in operation.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. In a compressor, the combination with a cylinder head having a discharge port passing through said head, a freely opening resilient valve flap for controlling said port, said valve having a portion thereof secured to said cylinder head at a point remote from said opening, means forming a fluid pocket in said head between said part and the point at which said valve flap is secured to said cylinder head, and means for admitting fluid to said pocket as said valve flap moves to open position so as to prevent the formation of a vacuum between said valve flap and the surface of said head.

2. In a compressor, a flrst member provided with a. gas passage, a second member centrally disposed within said passage and having a surface flush with a surface of said first member, a valve disc carried by said second member cooperating with said surfaces to control the flow of fluid through said passage, and a valve disc stop carried by said second member and arranged to limit the opening movement of said valve disc.

3. In combination with a piston adapted to be reciprocated within a cylinder of a compressor and having a passage therethrough for conveying a fluid from one side of the piston into the cylinder on the opposite side thereof, a valve support within said passage, a valve disc carried by said support and having one portion seating on said support and another portion seating on said piston, and means for frictionally holding said valve support in place within said passage during grinding of the valve seating surfaces.

4. In a compressor, a cylinder, a piston within said cylinder, said piston comprising an integral bucket having a port at its head end, valve mech anism for said port carried within said piston, means for reciprocating said piston having a portion secured to the inside wall of said bucket, and resilient means between said portion and said valve mechanism for resiliently holding said valve mechanism in place.

5. In a compressor valve, a valve mounting having a flat surface, an aperture through said mounting, means within said aperture smaller than said aperture having a flat surface in the plane of said first named surface, means for maintaining said surfaces in alignment comprising a spider member having a portion in engagement with said first named surface and having another portion in the plane of said first named portion and in engagement with said second named surface, and a valve disc engaging said surfaces to control the flow of fluid through said aperture.

6. In a compressor, the combination with a cylinder, a cylinder head having a discharge port and a streamlined passage leading to said port, a freely opening valve for controlling said port, a piston within said cylinder having an opening in one end, means carried by said piston extending into said opening and forming with the walls of said opening a streamlined passage, and a valve member cooperating with said streamlined passage.

'7. In a compressor, a member having a streamlined discharge port, a valve seat for said port, a valve flap for said port, means securing a portion of said flap to said member whereby fluid pressure on said flap causes said flap to occupy: a position at an angle to said valve seat, and

means for directing the flow of fluid through said member in a direction substantially parallel to the plane of the 'valve flap while in open position whereby fluid is free to flow through said port and past said valve without the formation of eddy currents within said port.

8. In a fluid circulating system, a first member having a fluid flow passage, a valve seat adjacent said passage, a second member disposed within said passage and having a valve seat thereon, a valve flap carried by said second member cooperating with said valve seats to control the flow of fluid through said passage, and a valve flap stop carried by said second member and arranged to limit the opening movement of said valve flap.

9. In a fluid circulating system, a cylinder, a piston within said cylinder, said piston comprising a bucket having a port at its head end, valve mechanism for said port carried by said piston, said mechanism comprising a member disposed within said port, a valve flap carried by said member, and means for maintaining said first member within said port, said last named means including means for limiting, the opening movement of said valve flap.

10. In combination with a member having a substantially flat surface provided with a streamlined valve port, a resilient valve flap secured to said flat surface at a point remote from said port and cooperating with said port to control the flow of fluid therethrough, said valve port and said valve flap being so constructed and arranged whereby fluid is free to flow through said port and past said valve without the formation of eddy currents within said port, means for preventing suction between said valve flap and a portion of said flat surface as said valve flap moves to open position comprising a pressure relief pocket in said flat surface between said port and the point at which said resilient valve flap is secured to said flat surface, and means for admitting fluid to said pocket as said valve flap moves to open-position.

WIILFORD H. 'I'EE'I'ER. 

